[GRASS-dev] Re: r.walk, r.cost & r.drain patches posted

[Michael Barton]

Maybe what is needed is a built in vectorization algorithm that will  
transform the paths to vectors is a flag is set.

Michael
____________________
C. Michael Barton, Professor of Anthropology
Director of Graduate Studies
School of Human Evolution & Social Change
Center for Social Dynamics & Complexity
Arizona State University

Phone: 480-965-6262
Fax: 480-965-7671
www: <www.public.asu.edu/~cmbarton>



On Jan 7, 2009, at 9:32 AM, Colin Nielsen wrote:

>> Thanks for the updates. I'll give them a try. While I understand  
>> the reason
>> for the gaps in the paths now, I think that it is important to find  
>> some way
>> to get rid of them. That is, there needs to be some algorithm that  
>> will
>> 'connect the dots' of knights move jumps.
>
> I certainly agree but it should be done without adding cells in
> between. The knight's moves should be retained in the output. We need
> some kind of vectorization algorithm which connects cell center to
> cell center, or which joins all the little line segments that would be
> produced by a discontinuous path.
>
>> Even without vectorizing, the cell accumulation
>> values will be inaccurate if cells are skipped in a path from point  
>> A to
>> point B.
>
> The algorithm accounts for the accumulation value in these larger
> jumps using pythagoras. Just as diagonals are multiplied by ~1.4,
> knight's move jumps are multiplied by ~2.2 (but depending on the
> resolution, etc.).
>
> -Colin